You demonstrate results from your past and current work. You build trust through word of mouth and reviews (amongst other things). Just be able to display results.

Start talking to businesses about how you've helped people. The main difference is that now instead of talking to an individual about how it can help them, you need to think of how this helps a business - businesses operate for one reason only, to make a profit. So how will your services create value for the business? Once you can succinctly explain this, start reaching out to businesses and open a line of discussion. Try to determine a good target market, though, as there are nearly an infinite number of businesses out there - who can you help the most and how?